1. Field of the Invention
The present invention relates to a filter for a satellite communication receiver, and more particularly, to a surface acoustic wave (SAW) filter for suppressing surface to surface interference with "C" band satellite communication signals for the region of 3.7 to 4.2 GHz.
2. Description of the Prior Art
In general, conventional filters for suppressing interference with satellite communication signals transmitted between earth stations are not installed inside of the satellite communication receiver, but are installed seperately outside of the receiver.
This type of filter is a kind of notch filter which suppresses the frequency f.sub.N range where the interference signal exists in the intermediate frequency (IF) band, and is typically comprised of a tuning circuit utilizing an inductor coil and a capacitor (as shown in FIG. 1). When the operational frequency range is increased to the region of several GHz, the frequencies of the unnecessary regions are suppressed by other filters utilizing strip lines.
However, such conventional filters for suppressing the interference with communication signals between earth stations have some drawbacks in that the manufacturing process becomes complicated and the size of the filter increases. In the case of the filter for use in the IF band utilizing an inductor coil and a capacitor (as shown in FIG. 1), it is necessary to adjust the inductor coil and capacitor in order to select the frequency range to be suppressed. In the case of the filter utilizing strip lines, the size of the filter will be increased when this filter is used for the IF band. Therefore, such conventional filters cannot be installed within the satellite communication receiver but must be installed outside of the receiver.